Blasting-bore closure



1,642,118 S p 13, 1927' w. LINDNER BLASTING BORE CLOSURE Filed Nov. 17.1926 Jnvemor:

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Patented Sept. 13, 1927.

PATENT OFFICE.

WERNER LINDNER, OF BEUTHEN, GERMANY.

BLASTING-BORE CLOSURE.

Application filed November 17, 1926, Serial No. 148,981, and in GermanyJuly 26, 1926.

This invention relates to improvements in blasting closures. Saidclosure is Preferably used in combination with a water filling of onepart of the blasting bore and comprises a plug proper having alongitudinal bore and means to operate like a non-return valve. Saidclosure bringing about a saving in blasting material and affordingperfect safety while the blasting work is carried out. The blasting boreis, to that effect, filled in the manner shown in the accompanyingdrawing, in which also the blasting bore plug is illustrateddiagrammatically and by way of example. Figure 1 is a longitudinalsection through a filled blasting bore ready for use, Figure 2 is partla side view of, and partly an axial section t rough a blasting bore plugdesigned according to this invention, this figure being drawn to aconsiderably increased scale relatively to Figure 1, and Figure 3 is anend-view of said plug.

On the drawing, 1 (Fig. 1) denotes the finished blasting bore, 2 theblasting substance introduced into its rear ortion, 3 the fuze for thissubstance, 4 a uze cord, and 5 a stopppr consisting of loam andpreventing the lasting substance 2 from leaving its place, as well asfrom gettin moist. The free end of the blasting bore is closed by a plugwhich is preferably conical and consists of wood or another suitablematerial. The details of this plug are shown in Figs. 2 and 3. Theblasting bore end is preferably so much enlarged that the plug g can beprovided with a packin 11 of plastic loam for tightening it in thelasting bore end. The plug 6 is provided with an axial channel 7 throughwhich water can be, and is, introduced, may "be by means of an ordinarysyringe, into the blasting bore space 1 between the stopper 5 and theplug 6 until this space ls comp etely filled. The water will be retainedin said space in most cases ahead by the ressure of the atmospheric air;only if gas nds access into the blasting bore the water will be forcedout of it, or of the s ace or chamber 1 respectively. In view oft ispossibility or from reasons of safety generally,

a piece of rubber film 8 is drawn over the inner face of the plug 6, aswell as over the rear end of the plug channel 7 and is secured in laceby a cord 9 wound round in a perip eral groove 10, as shown especiallyin Fig. 2. This simple elastic closing member (8) permits theintroduction of the water into the chamber 1, but prevents the waterfrom leaving said chamber in that it acts as a non-return valve. Ofcourse also another type of non-return value could be used.

When the blasting bore 1 has been filled and prepared in the mannerstated, and the blasting substance 2 is exploded, a very strong pressureis suddenly exerted upon the water which not only has a great inertiabut also cannot be compressed, the result bein that the action of theblasting substance is greatly intensified by that water pressure in thatit presses upon the blasting bore wall and rends the mineral. On theother side, however, the water forms a particularly effective protectionfrom the dangerous explosion of hydrocarbons as well as from coal dust,because it extinguishes at once the explosion flame.

I claim:

'1. A plug for closing the open end of a blasting bore, comprising, incombination, a plug proper having a longitudinal bore, and means rovidedat the inner face of this plug and a apted to operate like a non-returnvalve, for the urpose set forth.

2. A plug or closing the open end of a blasting bore, comprising, incombination, a plug proper having a lon itudinal bore, and a non-returnvalve provi ed at the inner end of said bore, for the purpose set forth.

3. A plug for closing the open end of a blasting bore, comprising, incombination, a plug roper havin a lon 'tudinal bore, and a rub r filmattac ed to t e rear end of said plug and covering the rear end of saidbore and being adapted to operate as a non-return valve for the saidbore, substantially and for the purpose set forth.

In testimony whereof I aflix mirggpature.

WERNER LI ER.

